Waste-heat cooling system for periodic clay-burning kilns



April 14, 1925.

R. L. ASH

TEM FOR PERIODIC CLAY BURNING KILNS WASTE HEAT COOLING SYS Filed Nov. 18, 1922 6 P i' A Ann up? Patented Apr. 14, 1925.

1,533,9iiti STATES iis'ifihi'if' @FMQEQ ROYAL L. ASH, OF BUCYRUS, OHIO. ASSEG-NOR OF (HIE-HALE TO KANE DES MOINES, IOU/A. v

0. return or W'ASTE-HEAT COOLING SYSTEM FOR PER-101316 CLAY-BUBNING KILNS.

Application filed November 18, 1922. Serial No. 601,850.

To all 107mm it may concern.

Be it known that I, ROYAL L. Aer-1, acitizen or the United States, and a resident of liucyrus, in the county of Crawford and State of @hio, have invented a certain new and useful WasteHeat Cooling System for Periodic Clay-Burning Kilns, of which the following is a specification.

lily invention relates to a system of utilising the waste heat from a periodic clayburning kiln for drying purposes.

The object of my invention is to provide a waste heat cooling system for periodic clay-burning kilns of simple and efiicient construction.

More particularly, it is the object of my invention to provide such a system embodying the use oi a permanently constructed internal, waste-heat fine for drawing waste heat from the interior of the kiln at thetop thereof and connected through an underground tunnel to the main waste heat tunnel.

A further purpose is to provide such a structure whereby the ware may be cooled in a shorter time than has been possible with the systems hereto-tore in use.

Another object is to provide such a structure, whereby the waste heat can be connected to the drier with a minimum loss of heat by radiation or otherwise, and whereby the maximum or" heat is made available for the drier.

This is especially accomplished by causing the heated gases to follow a natural path rather than in attempting to draw them in a path contrary to that naturally taken by heated gases, and also by the use of the internal flue and the underground passage.

Another object of my invention is to provide such a system, whereby a minimum of noxious and heavy gases are drawn into the drier.

Still a further object of my invention is to provide such a system so constructed and arranged as to afford definite control of the drying temperature thereby producing thoroughly dried ware. v

Another object is to provide such a system embodying a structure, which leaves no open ports in doorways of kilns and no open ports through which workmen might fall and injure themselves.

Another purpose is to provide such a structure that can be operated for utilizing the waste heat with a minimum of labor.

An additional object is toprovide such a system, which embodies a permanent installation at a low cost and eliminates temporary construction of any kind at the time the waste heat is to be drawn off.

This provides such a system, which permits cooling of the kiln during unloading or setting by drawing air through the doors of the kiln.

The structure of my system also allows access to both doors at all times.

With these and other objects in view, my invention consists in the construction, arrangement and combination'of the various parts of my system, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which: i I Figure 1 shows a vertical, sectional View through a portion of a kiln wall and crown, the waste heat flue and conducting passage and the main waste heat flue in a structure en'ibodying my invention.

Figure 2 shows a horizontal, sectional view taken on the line 2-2 of Figure l. v

Figure 3 shows a horizontal, transverse, sectional View through the passage taken on the line 33-ot Figure 1. i

Figure 4 shows a plan of the steel damper; and

' Figure 5 shows an elevation taken from the inside, illustrating the flue and a portion.

of the inside wall and bag walls of the kiln.

In practically all modern plants where periodic kilns for burning clay are employed, it is the practice to artificially dry the ware after its formation and before it is burned.

Economic practice requires that the heat. which is available in the kiln after the ware has been burnechand which would otherwise be wasted, be used in the driers or drying rooms.

The problem of taking the heat from the kiln and conducting it to the drier is one involving many diliiculties.

I will describe the structure of a system embodying my invention and will then refer to some of these diiiiculties and explain to some extent the advantages of my structure and the manner in which it solves such difficulties.

In the accompanying drawings, T have used the reference numeral 10 to indicate generally the upright wall of a kiln. Kilns are built round or rectangular and ordinarily have a dome-shaped crown or top 11. Ordinary kilns are provided on oppo-- site sides with doors 12.

In the wall are usually located the tire boxes 13 and on the interior of the kiln, the the bags or bag walls it are built up in semi-circular form with their open ends adjacent to the wall from the floor to a height above the fire boxes usually, but terminating considerably below the base of the crown.

There is ordinarily provided in a plant,

a main flue or tunnel 15, which leads to the drier and is designed to receive the waste heat from a series of kilns.

My system embodies the structure of a permanent flue 16 on the inside of the kiln. This flue 16 is built against the wall 10 and extends as high as it can be conveniently built, which is usually approximately to the base of the crown, as shown in Figure It extends downwardly below the kiln floor 17 as shown in Fig re 1.

Extending under the wall 10 ot the kiln and leading to the main line 15 and affording communication from the lower interior of the flue 16 to the main flue is a passage 18. That portion of this passage 18 between the kiln or flue or tunnel 15 should be underground in order to insure the mini mum loss of heat, and in order not to 1ntertere with the workmen.

The passage 18 has a port 19 in its top just outside the kiln. In the passage 18 near the port 19 and between that port and the main flue, there is provided a shoulder 20 against which a steel damper 21 may be fitted. This steel damper has a handle 22 for conveniently manipulating it, so that it may be taken from its position against the shoulder 20 and drawn out through the port 19 and used as a cover for such port.

then the ware is being. burned, a false wall 23, usually made of brick and plaster, is placed-in the passage 18 adjacent to the port 19 to prevent loss of heat during the burning.

The damper 21 is placed against the shoulder 20 for the purpose of closing the passage 18 and preventing connnunication between such passage and the main line, so that when the kiln under consideration is being used for burning, the main flue can be used for drawing waste heat from other kilns without drawing in cold air through the port 19 and without permitting the fan by which the gases are drawn through the kiln under consideration through the line 16 and the passage 18 into themain flue.

lit will be understood that the steel damper 21 is laid over the port 19 for forming a closure for keeping out cold air.

In order to make clear the operation and advantages of my system, it may be well to mention that the ordinary method now used for drawing the waste heat from the kiln to the main flue leading to the drier involves breaking holes in the false walls, 8

which were built in the door bet'ore the ware was burned.

A large metal goose-neck is then placed with one end adjacent to the hole in the outer false wall of the door and with the other end communicating with the port in the top of the main flue. These goose-necks are clumsy and it usually takes from four to men to place them in position. The use of these goose-necks results in an iminense loss of heat by radiation. The life oi the goose-neck is about two years.

The old system referred to involves the provision of ports in the main flue. These ports are usually covered by iron. plates, which sometimes become misplaced with the result that men or animals are injured by tailing into the port. Where there are numerous ports of the kind mentioned in the main line, there is a consequent loss of heat through them when they are covered and the goose-necks are not being used.

The old system now under consideration draws the waste heat from the kiln diagonally downward in a path at an acute angle to the natural upward path of the heated gases.

My system permits the pulling off of the heated gases and the cooling of the ware in the kiln in about half the time required, where the goose-neck system mentioned above is employed.

The heat in the kiln at the time when the burning is finished may be as high as 2200 the door of the lower part of the kiln wall, the pull into the main waste-heat flue is not only contrary to the natural direction of movement and pull of the gases in the kiln,

but it is in, a diagonal path and tends to draw the gases in a crooked path against and around the ware.

lVith my system, the gases are drawn first from the top of the kiln and then gradually from each lower part of the kiln, so that when the ware in the lower part of the kiln is once cooled, it stays cool and there is only one withdrawal of the gases in the same path.

WVhere the gases are drawn off through the door, as by the old goose-neck system abovemeutioned, the gases in the lower part ofthe kiln are pulled out first. However, on account of the direction of the pull of the gases on the interior of the kiln and the location of the outlet in the door, the hot gases from the top of the kiln are constantly pulled downwardly through the ware that would otherwise be coolin This sometin'ies results in the checking of the ware.

here my system is used and the gases are drawn from the top of the kiln first, the ware cools at the'bottom first and then gradually cools toward the top of the kiln, and I find that I do not have any such checking under such circumstances.

My system makes available for the drier a maximum of heat from the kiln.

It is obvious that the radiation loss, which would occur where the goose-neck is used is almost wholly avoided by my system. The heated gases are drawn down through the flue, which is on the inside of the kiln and which is hot at the time the heated gases begin to go through it, and remains hot until the hot gasesare all pulled out.

I avoid the loss of heat which where there are joints between the goose neck and the door and between the gooseneck and the tunnel or flue, where the old system is employed.

My passage is underground and I hence lose very little heat there.

There is no infiltration of cold outside air into my fine or passage, and I thus have another advantage over the goose-neck or other similar system where such infiltration would occur.

It is obvious that the old goose-neck system is aiii'ec-ted by atmospheric conditions, and that in cold weather, more heat would be lost than in warm weather. This fact makes it more dihicult with the old system to control and regulate the heat in the drier.

Where my system is employed, the heat in the drier can be accurately regulated. If more heat'is desired, the workman simply knocks out another brick or two in the false occurs through the heated ware during the operation and are consumed.

I also avoid open ports in the mainline and eliminate the danger of injury to men or animals on account of such ports.

It will be noted that my port 19 is very close to the kiln and arranged above ground level, so that there is very little danger of men falling into it. lVhere the ports in the main flue are thus eliminated, I do away with the possibility of. rain water entering the waste-heat tunnel.

The labor required for operating my system, as will be seen from the foregoing explanation is very little and can be done by one man, whereas with the old goose-neck system, from four to six men were required to set the goose-neck, and on account of its weight and awkward construction, men are sometimes injured in setting it and in removing it.

My installation is a permanent one, and the up-keep after installation is almost negligible. Where my system is employed, the kiln can be cooled during unloading or setting by drawingcold air through the doors over the workmen.

An important advantage of my system over any system which draws off the'gases through the door arises from the fact that where my system is employed, both doors are available for use at all times.

For instance, where the old goose-neck system is employed, it is sometimes desirable to open one door andbegin unloading the ware at a time when the goose-neck must be left installed at the other door, and thus only one door is available. I

Where my system is employed, both doors can be opened and cold air will rush in, and men can work through both doors for takin out the ware.

31y structure is also frequently advantageous in this respect in setting the ware in the kiln. I

After the ware has cooled down to where it can be handled, the fire boxes can all be sealed and cold air can be pulled in through the door, making it possible for the men to work with the ware sooner than would otherwise be possible.

It will be noticed that where my systcni is employed, the flue can be located at any desired point on the interior of the kiln, so

as to afford the shortest passage from the flue in the kiln to the main waste heat flue. Where the heat is taken. off through the door, the distance from the door to the main flue may be considerable.

Hy process, as will be seen from the fore going, embodies drawing the waste heat, by suction, from the top of the kiln through an interior flue, subject to the heat in the kiln, and the controlling of the flow and temperature of such gases by the manner set forth.

I claim as my invention:

1. A waste heat cooling system comprising the combination of a kiln and a waste heat tunnel, with a flue arranged on the interior of the kiln, adjacent to the wall thereof, having its upper end open at the top of the kiln, a passage leading from the bottom of the line to said tunnel, said passage having a port outside said kiln, a movable closure member in said passage between the port and the tunnel, and a false wall in the passage between the port and the fine.

2. A waste heat cooling system comprising the combination of a waste heat tunnel and a kiln with a flue arranged adjacent to the wall of the kiln and communicating with the interior of the kiln at the top thereof,'a passage leading from the bottom of said fine to said tunnel, having a port outside the kiln, a movable closure member in the passage between the port' and the tunnel and a removable closure member in the passage between the port and the flue.

A waste heat cooling system comprising the combination of a waste heat tunnel and a kiln, having a door, and a plurality of bag walls, with a permanent flue on the interior of the kiln adjacent to the wall of bag walls, with a permanent fine on the interior of the kiln adjacent to the wall thereof open at its upper end close to the top of the kilnyand extending through the floor of the kiln, an underground passage leading from the lower end of the line to the tunnel, having a port outside the k means for closing said port, adjustable for admitting air, and a removable false wall element in the passage between the port andthe flue.

5. A waste heat cooling system comprising the combination of a waste heat tunnel and a kiln, having a door, and a plurality of bag walls, with a permanent flue on the interior of the kiln adjacent to the wall thereof open at its upper end close to the top of the kiln and extending through the floor of the kiln, an underground pas age leading from the lower end of the line to he tunnel, having a port outside the kiln, a shoulder in the passage between the port and the tunnel, said device having means for coacting with said shoulder and closing said passage and for adjustably closii'ig said port, and a false wall element inthe passage between the port and the flue.

Des Moines, Iowa, September 20, 1922. ROYAL L. ASH. 

